Battery module

ABSTRACT

Embodiments of the present disclosure relate to a battery module. According to an embodiment of the present disclosure, there is provided a battery module including a plurality of battery cells each including at least one electrode tab, and a bus bar in contact with the electrode tabs to electrically connect the plurality of battery cells, wherein the bus bar includes a plate in which a plurality of holes are formed, and the electrode tabs are inserted into at least a portion of the plurality of holes to electrically connect the plurality of battery cells.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/363,725 filed on Jun. 30, 2021, which is a continuation of U.S.patent application Ser. No. 15/850,852 filed on Dec. 21, 2017 and issuedas U.S. Pat. No. 11,088,410 on Aug. 10, 2021, which claims priority toand the benefit of Korean Patent Application No. 10-2016-0177900, filedon Dec. 23, 2016, Korean Patent Application No. 10-2017-0041875, filedon Mar. 31, 2017 and Korean Patent Application No. 10-2017-0177048,filed on Dec. 21, 2017. The disclosures of which are incorporated hereinby reference in their entirety.

BACKGROUND 1. Field of the Invention

Exemplary embodiments of the present disclosure relate to a batterymodule.

2. Discussion of Related Art

More powerful secondary batteries that can be charged and dischargedmany times are actively being researched due to their use in advancedfields such as digital cameras, cellular phones, laptop computers,hybrid vehicles, and the like. Examples of secondary batteries include anickel-cadmium battery, a nickel-metal hydride battery, anickel-hydrogen battery, and a lithium secondary battery. The lithiumsecondary battery typically has an operating voltage of 3.6 V or higherand can be used as a power source for portable electronic devices. Also,a plurality of lithium secondary batteries connected in series can beused to power a high-output hybrid vehicle. Use of the lithium secondarybattery has rapidly increased because its operating voltage thereof isapproximately three times higher than that of the nickel-cadmium batteryor the nickel-metal hydride battery. Also, the lithium secondary batteryhas excellent energy density per unit of weight.

Typically, a bus bar is brought into contact with the electrode tabs ofbattery cells for connecting a plurality of battery cells. Aconventional bus bar is formed to have a C shape. Electrode tabs may bebrought into contact with a C-shaped bus bar so that two or more batterycells can be electrically connected. Connecting the battery cells mayrequire at least one of cutting and bending the electrode tabs of thebattery cells. As the number of battery cells, e.g. three battery cells,four battery cells, or the like (that is, parallel connection of threecells or parallel connection of four cells) to be connected varies, thecutting and bending dimensions of electrode tabs also vary. Becauseexisting battery modules require deforming the electrode tabs forcoupling the battery cells, the number of required process operations isincreased, which in turn renders the manufacturing process morecomplicated and increases its cost.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure provide a battery module allowingthe number of assembling processes to be reduced due to electrode tabprocessing for electrically connecting a plurality of battery cellsbeing simplified.

Other embodiments of the present disclosure provide a battery modulecapable of preventing deformation of shapes of electrode tabs by a shapeof a bus bar being deformed.

Other embodiments of the present disclosure provide a battery moduleallowing costs to be reduced according to a reduction in the number ofprocesses.

Other embodiments of the present disclosure provide a battery modulecapable of uniformly melting electrode tabs when a plurality of batterycells are electrically connected to each other.

Other embodiments of the present disclosure provide a battery moduleallowing a connection state to be visually confirmed when a plurality ofbattery cells are electrically connected by welding or the like.

According to an aspect of the present disclosure, there is provided abattery module including a plurality of battery cells each including atleast one electrode tab, and a bus bar in contact with the electrodetabs to electrically connect the plurality of battery cells, wherein thebus bar includes a plate in which a plurality of holes are formed, andthe electrode tabs are inserted into at least a portion of the pluralityof holes to electrically connect the plurality of battery cells.

Each of the plurality of electrode tabs may be inserted into thecorresponding one of the plurality of holes and fixed.

The electrode tab may be inserted into one side of the plate andprotrude to the other side of the plate.

The electrode tab may protrude by a length of 1 to 3 mm from an outerend of the hole.

The plate may include a protruding portion formed at a periphery of aposition at which the hole is formed.

A cross-section of the periphery of the hole may be formed to be taperedtoward one side of the plate so that the electrode tab may be insertedinto the hole.

A width of an entry space into which the electrode tab enters at the oneside of the plate may be reduced near the hole.

The plate may include a tab connection portion configured to protrudefrom an outer periphery of the hole to an outside of the plate.

The electrode tab and the plate may be connected to have a wobblewelding shape by laser welding.

The hole may be formed to correspond to a thickness and a length of theelectrode tab.

A sum of both gaps between the hole and the electrode tab inserted intothe hole may range from 0.1 mm to 0.2 mm.

The electrode tab may be formed in a straight line without being bent.

At least one electrode tab includes a bent portion and a straightportion, and at least a part of the straight portion is inserted intoits respective hole.

The at least one electrode tab may include an insulating portion formedon at least a portion of the electrode tab, and the bent portion may beformed on the insulating portion.

The battery module may further include a support plate in which aplurality of support holes corresponding to the holes are formed and thesupport plate may be located between the plurality of battery cells andthe bus bar.

The bent portion may be formed at the electrode tab and the bent portionmay be supported to be in contact with one side of the support hole.

The battery module may further include a fixing plate in which aplurality of bus bar exposure holes corresponding to the holes areformed and the bus bar may be located between the support plate and thefixing plate and may be fixedly supported thereby.

A plurality of bus bars may be provided, at least two of the pluralityof electrode tabs may be connected to at least one of the plurality ofbus bars in parallel to form a parallel assembly, and a plurality of theparallel assemblies may be provided and connected in series or inparallel.

According to another aspect of the present disclosure, there is provideda method of manufacturing a battery module including providing aplurality of battery cells stacked in parallel next to each other, eachbattery cell including an electrode tab, providing a bus bar comprisinga plurality of holes formed at a regular interval and configured toreceive the plurality of electrode tabs, positioning the bus baradjacent to the battery cells so that the plurality of holes of the busbar are positioned adjacent to the plurality of corresponding electrodetabs, inserting the plurality of electrode tabs into the correspondingholes of the bus bar, and fixing the electrode tabs to the bus bar.

The electrode tab may protrude toward the other side of the plate.

The electrode tab may protrude by a length of 1 to 3 mm from an outerend of the hole.

The said fixing operation may include welding the electrode tabs to thebus bar.

The said welding operation may include laser welding of only theelectrode tabs and not of the bus bar.

The laser may be repeatedly applied to an end surface of the electrodetab in a shape of a circle, and centers of the circles may be locatedalong an axis of a longitudinal direction of the end surface.

The laser may be applied to the electrode tab obliquely with respect toa central axis of a longitudinal direction thereof.

A support plate may be arranged between the plurality of battery cellsand a bus bar, and the electrode tab may be positioned to pass through asupport hole of the support plate.

The bus bar may be coupled to at least a portion of the support plateand may be fixedly supported thereby.

A fixing plate may be arranged at another side of the bus bar, and thehole may be exposed to the outside through a bus bar exposure hole ofthe fixing plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent to those of ordinary skill in theart by describing exemplary embodiments thereof in detail with referenceto the accompanying drawings, in which:

FIG. 1 is a view illustrating a secondary battery according to anembodiment of the present disclosure;

FIG. 2 is a view illustrating a state in which a bus bar is brought intocontact with the secondary battery according to an embodiment of thepresent disclosure;

FIGS. 3A and 3B are views illustrating the bus bar according to anembodiment of the present disclosure;

FIG. 4A is a cross-sectional view illustrating the bus bar according toan embodiment of the present disclosure;

FIG. 4B is a cross-sectional view illustrating a state in which anelectrode tab is inserted into a hole of the bus bar according to anembodiment of the present disclosure;

FIG. 5A is a cross-sectional view illustrating the bus bar according toan embodiment of the present disclosure;

FIG. 5B is a cross-sectional view illustrating a state in which anelectrode tab is inserted into a hole of a bus bar according to anembodiment of the present disclosure;

FIG. 6 is a view illustrating a state in which a bent portion is formedon an insulating portion of the electrode tab;

FIG. 7A is a view illustrating a secondary battery according to anembodiment of the present disclosure;

FIG. 7B is an enlarged view of a portion A of FIG. 7A;

FIG. 8 is a perspective view illustrating a support plate, a bus bar,and a fixing plate according to an embodiment of the present disclosure;

FIG. 9 is a view illustrating a state in which the support plate, thebus bar, and the fixing plate of FIG. 8 are coupled;

FIG. 10 is a cross-sectional view taken along line A-A′ of FIG. 9 ;

FIG. 11A is a front view illustrating an electrical connection state ofa battery module according to an embodiment of the present disclosure;

FIG. 11B is a rear view illustrating an electrical connection state ofthe battery module according to an embodiment of the present disclosure;

FIG. 12A is a cross-sectional view illustrating a bus bar according toan embodiment of the present disclosure;

FIG. 12B is cross-sectional view illustrating a state in which anelectrode tab is inserted into a hole of the bus bar according to anembodiment of the present disclosure;

FIGS. 13A and 13B are views illustrating the bus bar according to anembodiment of the present disclosure;

FIG. 14A is a cross-sectional view illustrating the bus bar according toan embodiment of the present disclosure;

FIG. 14B is a cross-sectional view illustrating a state in which theelectrode tab is inserted into the hole of the bus bar according to anembodiment of the present disclosure;

FIG. 15 is a cross-sectional view illustrating a position at which laserwelding is performed on a protruding electrode tab according to anembodiment of the present disclosure;

FIGS. 16A and 16B are views illustrating a state in which laser weldingis performed on the electrode tab according to an embodiment of thepresent disclosure; and

FIGS. 17A and 17B are views illustrating a state in which a laser isapplied to the electrode tab at an angle with respect to a longitudinaldirection of the electrode tab according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the drawings. However, we notethat these embodiments are only examples of the present invention andare not intended to limit the present disclosure.

The drawings are not necessarily to scale and, in some instances,proportions may have been exaggerated in order to clearly illustratefeatures of the embodiments.

It will be further understood that when an element is referred to asbeing “connected to”, or “coupled to” another element, it may bedirectly on, connected to, or coupled to the other element, or one ormore intervening elements may be present. In addition, it will also beunderstood that when an element is referred to as being “between” twoelements, it may be the only element between the two elements, or one ormore intervening elements may also be present.

Detailed descriptions of well-known structures and functions which mayunnecessarily obscure the present disclosure are omitted. Some termsdescribed below are defined in consideration of functions in the presentdisclosure, and meanings thereof may vary depending on, for example, auser or operator's intentions or customs. Therefore, the meanings ofterms should be interpreted on the basis of the scope of the presentdisclosure throughout this specification.

Hence, it should be understood that the spirit and scope of the presentinvention are defined by the appended claims and that the followingembodiments serve the purpose of describing the technological scope ofthe present invention to those skilled with ordinary skill in the art towhich the present invention belongs.

Hereinafter, the various embodiments of the present invention will bedescribed in detail with reference to the attached drawings.

FIG. 1 is a view illustrating a secondary battery 10 according to anembodiment of the present disclosure. FIG. 2 is a view illustrating astate in which a bus bar 20 a is arranged on the secondary battery.FIGS. 3A and 3B are views illustrating the bus bar 20 a. In describingthe secondary battery 10 and the bus bar 20 a, references will be madeto FIGS. 1, 2, 3A, and 3B.

Referring to FIG. 1 , the secondary battery 10 may include a pluralityof battery cells 11 and electrode tabs 12 drawn from the battery cells11.

Referring to FIG. 2 , the bus bar 20 a according to the embodiment ofthe present disclosure may have a shape in which holes 23 a (shown inFIG. 3B) are formed in a plate 21 a (shown in FIG. 3 ). A plurality ofholes 23 a may be formed in the plate 21 a, and an electrode tab 12 iswelded to each of the holes 23 a so that a plurality of welded batterycells 11 may be electrically connected. Since the electrode tabs 12 areinserted into the respective holes 23 a, it is not necessary to deformthe shape of the electrode tabs 12. The number of the plurality of holes23 a which are formed in the plate 21 a of the bus bar 20 a correspondto the number of the battery cells 11 to be connected thereto via thebus bar 20 a. Therefore, the battery cells 11 may be electricallyconnected without changing the shape of the electrode tabs 12 regardlessof the number of battery cells 11 to be connected in order toelectrically connect the battery cells 11. Details of the plate 21 a andthe holes 23 a will be described below.

Referring to FIGS. 3A and 3B, the bus bar 20 a may include the plate 21a, protruding portions 22 a, and the holes 23 a. The plurality of holes23 a are formed in the plate 21 a at predetermined intervals, and eachmay have a suitable shape and sufficient size so that the electrode tabs12 can be inserted into the holes 23 a for electrically connecting theplurality of battery cells 11. Each electrode tab 12 may be welded tothe plate 21 a after it is inserted into a corresponding hole 23 a.Therefore, the plurality of welded battery cells 11 may be electricallyconnected. In the illustrated embodiment, each hole 23 a may be formedto have a slit shape.

An area or size of the plate 21 a may be determined according to thenumber of the battery cells 11 welded to the plate 21 a. For example,when two battery cells 11 are electrically connected, the plate 21 a maybe formed to have an area or size to accommodate the two holes 23 a inwhich the two electrode tabs 12, one from each of the two stackedbattery cells 11, may be welded. Similarly, when three battery cells 11are electrically connected, the plate 21 a may be formed to have an areaor size to accommodate the three holes 23 a in which the three electrodetabs 12, one from each of the three stacked battery cells, 11 may bewelded. Hence, the area or size of the plate 21 a is determinedaccording to the number of the battery cells 11 to be connected. Usingthe bus bar 20 a according to an embodiment of the present disclosure,the battery cells 11 are electrically connected without having to changethe shape of the electrode tabs. By changing the area or size of theplate 21 a and the number of the holes 23 a according to the number ofthe battery cells and their individual size, the bus bar 20 a of thepresent invention can electrically couple the battery cells togetherwithout the need to change the shape of the electrode tabs 12 and/or cutthe electrode tabs 12. Hence, unlike existing techniques, which are usedfor electrically coupling a plurality of battery cells to form a batterymodule, there is no need to employ an additional process of abutting theelectrode tabs 12 to the bus bar which requires bending the electrodetabs 12, deforming the shape of the electrode tabs 12, and sometimeseven cutting the electrode tabs. When the bus bar 20 a of the presentdisclosure is used, only the steps of inserting the electrode tab 12 inthe bus bar 20 a and then connecting the electrode tab 12 and the busbar 20 a via welding are employed. Thus, bus bar 20 a in accordance withthe embodiment of the present disclosure simplifies the method ofinstalling the bus bar for electrically coupling a plurality of batterycells to form a battery module. Specifically, as explained above, thepresent invention bus bar makes the abutting step by bending, deforming,and cutting of the electrode tab 12 unnecessary.

The protruding portions 22 a may be formed at the bus bar 20 a and havea convex shape according to the embodiment of FIGS. 3A and 3B. Each ofthe protruding portions 22 a may be formed at a position at which acorresponding hole 23 a is formed in the plate 21 a. The protrudingportions 22 a are shaped to induce the electrode tab 12 to be insertedinto the hole 23 a. An enlarged view shown in FIG. 3B illustrates thatthe hole 23 a is formed in the protruding portion 22 a. Since the hole23 a is formed to correspond to a thickness T₁ and a length L₁ of theelectrode tab 12, the hole 23 a may be formed in the plate 21 a to havea area corresponding to the thickness T₁ of the electrode tab 12.Therefore, each protruding portion 22 a serves to more easily insert acorresponding electrode tab 12 into the hole 23 a formed within theprotruding portion 22 a. Details thereof will be described withreference to FIGS. 5A and 5B.

The plurality of holes 23 a may be formed in the plate 21 a atpredetermined intervals. The predetermined interval may be determinedaccording to an interval between the battery cells 11 which in turndepends upon the width of the battery cells 11. Specifically, thepredetermined interval may be determined according to a position atwhich the electrode tab 12 is inserted into the hole 23 a. The number ofthe holes 23 a may be determined according to the number of the batterycells 11 to be electrically connected.

Further, the hole 23 a may be formed to have a width L₂ corresponding tothose of the electrode tab 12. See FIG. 4A. The depth of the hole L₆(shown in FIG. (A)) may correspond to the width of the plate 20 a. Thehole 23 a may be formed to have a depth L₆ at which a state of theinserted electrode tab 12 may be maintained before welding. Theelectrode tab 12 is inserted into the hole 23 a and is in contact withthe plate 21 a so that the bus bar 20 a can be maintained in place evenbefore the welding takes place. Securing the electrode tabs 12 withinthe respective holes 23 a of the plate 21 a may also be advantageous forfacilitating the next step of welding the electrode tabs 12 with theplate 21 a of the bus bar 20 a.

The electrode tab 12 may be welded to the plate 21 a in a state in whichthe electrode tab 12 is inserted into the hole 23 a and is in contactwith the plate 21 a. Therefore, the plurality of battery cells 11 weldedto the bus bar 20 a may be electrically connected.

FIGS. 4A and 4B are views illustrating the bus bar 20 a according to anembodiment of the present disclosure. FIG. 4A is a cross-sectional viewillustrating the bus bar 20 a, and FIG. 4B is a cross-sectional viewillustrating a state in which the electrode tabs 12 are inserted intothe holes 23 a of the bus bar 20 a.

Referring to FIGS. 4A and 4B, the holes 23 a may be formed at the plate21 a at predetermined intervals of the plate 21 a. The electrode tabs 12may be inserted into the holes 23 a. The hole 23 a may be formed tocorrespond to the thickness T₁ and the length L₁ of the electrode tab 12so that the electrode tab 12 inserted into the hole 23 a may be incontact with the plate 21 a. In the exemplary embodiment of FIGS. 4A and4B, three holes 23 a may be formed in the plate 21 a constituting onebus bar 20 a. Thus, in this exemplary case, three battery cells 11welded through the holes 23 a may be electrically connected. However,the present disclosure is not limited thereto, and any suitable numberof holes 23 a may be formed according to the number of batter cells 11to be connected.

Each hole 23 a may be formed within a corresponding protruding portion22 a as illustrated in FIGS. 4A and 4B. Having the protruding portions22 a is advantageous for more easily guiding and inserting the tabs 12into their corresponding holes 23 a. However, in embodiment of thepresent disclosure, the plate may not have any protruding portions,e.g., the plate may be substantially flat and may only have holes 23 aconfigured to receive the corresponding tabs 12. Referring again to theembodiment of FIGS. 4A and 4B, each hole 23 a may have a wider entrypart starting with a wider width L₄ at one side of the plate 21 a and anarrower width L₂ at some depth inside the plate 21 a. Because of thisshape of the entry part of the hole 23 a, the electrode tab 12 can bemore easily inserted into the narrower part of the hole 23 a, which hasa width L₂. The entry part of each hole 23 a may also facilitate theprecise positioning of the bus bar 20 a so that the corresponding tabs12 may be readily inserted into the holes 23 a prior to the weldingstep.

FIGS. 5A and 5B are views illustrating the bus bar 20 a according to anembodiment of the present disclosure. FIG. 5A is a cross-sectional viewof the bus bar 20 a and FIG. 5B is a cross-sectional view illustrating astate in which the electrode tabs are inserted into the holes 23 a ofthe bus bar 20 a.

Referring to FIGS. 5A and 5B, each electrode tab 12 may include a bentportion 121. In this illustrated embodiment of FIGS. 5A and 5B, the bentportion 121 may have a U shape. The bent portion 121 may be formed by apredetermined portion of the electrode tab 12 being bent. However, thepresent disclosure is not limited thereto. That is, in a variation ofthe illustrated embodiment, a protruding portion may be formed on thepredetermined portion of the electrode tab 12 and other bent portions121 may be formed. When external vibration or impact occurs in a statein which the electrode tabs 12 are coupled to the bus bar 20 a bywelding, the bent portions 121 may absorb the impact at least partially,and thus reduce or prevent any damage to the coupling between theelectrode tab 12 and the bus bar 20 a and any damage to the electrodetabs 12.

Furthermore, when the electrode tabs 12 are inserted into the bus bar 20a, the bus bar 20 a may be mounted and fixed on the bent portion 121 ofthe electrode tab 12, a gap L₃ (illustrated in FIG. 15 ) between theelectrode tab 12, which is in an inserted state that will be describedbelow, and the hole 23 a of the bus bar 20 a may be constantlymaintained, a position of the electrode tab 12 inserted into the hole 23a may be fixed, and thus a welding line may be easily traced when theelectrode tab 12 is welded later. In addition, the bent portion 121 maybe brought into close contact with the one side of the plate 21 a toprevent a laser L (illustrated in FIG. 17 ) from being directly appliedto the battery cell 11 during the welding process.

Meanwhile, the position of the bent portion 121 is not limited thereto,and the bent portion 121 may be spaced at a predetermined distance fromthe hole 23 a, as illustrated in FIG. 10 , as will be described below inmore detail. That is, the bent portion 121 may be positioned to be incontact with one side of an outer circumferential surface of a supporthole 32 of a support plate 30 while being spaced apart from the hole 23a. A detailed description thereof will be given below.

Meanwhile, at least one electrode tab 12 may include the bent portion121 and a straight portion, and at least a part of the straight portionmay be inserted into its respective hole 23 a. The straight portion maymean an unbent portion of the electrode tab 12. Also, the straightportion may mean a straight part of the electrode tab 12 without bendingadditionally although the straight portion may include some fine curveduring the process.

Meanwhile, the predetermined portion may be a portion between a portioninserted into the hole 23 a and a portion of the battery cell 11 atwhich the electrode tab 12 is drawn. As described above, a length L₇ ofan unbent portion of an outside of the bent portion 121 of the electrodetab 12, when the electrode tab 12 is inserted into the hole 23 a, may bedefined by the bent portion 121 formed at the predetermined portion ofthe electrode tab 12.

The electrode tab 12 may be inserted into the hole 23 a and fixed by thebent portion 121. The length L₇ of the unbent portion of the outside ofthe bent portion 121 of the electrode tab 12 may be adjusted by the bentportion 121 according to a position at which the bent portion 121 isformed at the electrode tab 12. Referring to the process of insertingthe electrode tab 12 in the hole 23 a, while the electrode tab 12 isinserted into the holes 23 a, the bent portion 121 formed on theelectrode tab 12 may be brought into contact with the plate 21 a andlocked. Therefore, the electrode tab 12 may be inserted into the hole 23a just above a position of the electrode tab 12 at which the bentportion 121 is formed and fixed. Meanwhile, the above-described lengthL₇ of the unbent portion of the outside of the bent portion 121 of theelectrode tab 12 may be greater than the depth L₆ of the hole 23 a.

In the bus bar 20 a according to the embodiment of the presentdisclosure, in order to firmly weld the hole 23 a formed in the bus bar20 a and the electrode tab 12 inserted into the hole 23 a, a gap L₃(that is, any one of gaps at both sides of the electrode tab 12 insertedinto the hole 23 a) between the hole 23 a and the electrode tab 12 mayhave a predetermined size or less, and the predetermined size may be 0.2mm. When the gap L₃ between the hole 23 a and the electrode tab is morethan 0.2 mm, it may be difficult to connect the hole 23 a and theelectrode tab 12 by laser welding. More preferably, the gap L₃ betweenthe hole 23 a and the electrode tab 12 may be 0.1 mm or less. Forexample, when the width L₂ of the hole 23 a formed in the bus bar 20 ais 0.5 mm, the thickness T₁ of the electrode tab 12 is set to 0.3 mm ormore, and thus each of gaps L₃ between the holes 23 a formed at bothsides of the electrode tab 12 and both sides of the electrode tab 12 maybe 0.1 mm ((0.5−0.3)/2) or less.

The bus bar 20 a may also melt during the welding process, and there maybe insufficient insertion in the process of inserting the electrode tab12 when there is no difference between the thickness T₁ of the electrodetab 12 and the size of each of the holes 23 a. Thus, each of the gaps L₃between the hole 23 a and both sides of the electrode tab 12 insertedtherein should be about 0.05 (0.1/2) mm or more. That is, a sum of thegaps L₃ between the hole 23 a and both sides of the electrode tab 12inserted into the hole 23 a may range from 0.1 mm to 0.2 mm.

Accordingly, only the electrode tab 12 may melt during laser welding ina process of manufacturing the battery module 1 that will be describedbelow.

Meanwhile, the electrode tab 12 may be formed of any one of copper (Cu)and aluminum (Al). For example, when a positive electrode tab is made ofcopper (Cu), a negative electrode tab may be made of aluminum (Al), andvice versa. In this case, thicknesses T₁ of the positive electrode taband the negative electrode tab may also vary. When the electrode tab ismade of copper (Cu) due to characteristics of the positive electrode andthe negative electrode tab, the thickness T₁ of the electrode tab may beabout 0.3 mm, and when the electrode tab is made of aluminum (Al), thethickness T₁ of the electrode tab may preferably be about 0.4 mm.Therefore, the width L₂ of the hole 23 a of the bus bar 20 a may beabout 0.5 mm. However, the thickness T₁ of the electrode tab 12 and thewidth L₂ of the hole 23 a are not limited thereto, and it should beobvious that the thickness T₁ of the electrode tab 12 and the width L₂of the hole 23 a may be changed as necessary.

FIG. 6 is a view illustrating a state in which a bent portion 121 isformed on an insulating portion 125 of the electrode tab 12.

Referring to FIG. 6 , the battery cell 11 may include an electrodeassembly and an exterior material configured to surround the electrodeassembly. In this case, the electrode tab 12 may include a terraceportion 124 formed by an exterior material being bonded along a sideedge of the electrode assembly in which the electrode tab 12 protrudes,an insulating portion 125 that can increase a degree of sealing of theexterior material at a position at which the electrode tab 12 is drawnfrom the terrace portion 124 with securing an electrically insulatedstate, and an electrode tab portion 126 that is drawn from theinsulating portion 125 and having at least a portion thereof insertedinto the hole 23 a being bound. The bent portion 121 may be formed onthe insulating portion 125.

Specifically, the bent portion 121 may be formed by the electrode tabportion 126 being bent outside the insulating portion 125, but thepresent disclosure is not limited thereto, and the bent portion 121 maybe formed on the insulating portion 125 by the insulating portion 125 ofthe electrode tab 12 being bent. As described above, as the bent portion121 is formed on the insulating portion 125, an overall length L₁ of theelectrode tab 12 may be reduced, reducing the overall volume of thebattery module 1.

Furthermore, when the bent portion 121 is formed on the insulatingportion 125, bending may be performed within a range in which theinsulating material of the insulating portion 125 is not torn ordamaged, and thus a volume occupied by the electrode tab 12 in thebattery module 1 may be reduced while insulation performance of theinsulation portion 125 is maintained, and an energy density of thebattery module 1 may also be increased.

FIG. 7A is a view illustrating a secondary battery according to anembodiment of the present disclosure, and FIG. 7B is an enlarged view ofa portion A of FIG. 7A.

Meanwhile, referring to FIGS. 7A and 7B, chamfer portions 127 may beformed at both side ends of the electrode tab 12 so that the electrodetab 12 may be easily inserted into the hole 23 a when the electrode tab12 is inserted into the hole 23 a.

Specifically, both side edges of the electrode tab 12 in a direction d₂of the length L₅ of the end surface of the electrode tab 12 may be cutobliquely with respect to a direction d₁ of the length L₁ of theelectrode tab 12, and the chamfer portions 127 may be formed on both ofthe side ends of the electrode tab 12. Since the chamfer portions 127are formed at the ends of the electrode tab 12 as described above,insertion of the electrode tab 12 into the hole 23 a may be induced in aprocess of inserting the electrode tab 12 into the hole 23 a, and theinsertion of the electrode tab 12 may be facilitated.

FIG. 8 is a perspective view illustrating a support plate 30, a bus bar20 a, and a fixing plate 40 according to an embodiment of the presentdisclosure. FIG. 9 is a view illustrating a state in which the supportplate 30, the bus bar 20 a, and the fixing plate of FIG. 8 are coupled.FIG. 10 is a cross-sectional view taken along line A-A′ of FIG. 9 .

FIG. 9 is a view illustrating a state in which a plurality of secondarybatteries are not connected to an assembly of the support plate 30, thebus bar 20 a, and a fixing plate 40, and FIG. 10 is a view illustratinga state in which the electrode tab 12 is inserted into one side of theassembly of the support plate 30, the bus bar 20 a, and the fixing plate40. Referring to FIGS. 8 to 10 , the battery module 1 according to anembodiment of the present disclosure may further include the supportplate 30 in which a plurality of support holes 32 corresponding to theholes 23 a of the bus bar 20 a are formed. In this case, the supportplate 30 may be located between the plurality of battery cells 11 andthe bus bar 20 a to fixedly support the bus bar 20 a.

Specifically, the support plate 30 may include a plate-shaped supportplate body 31 and a plurality of support holes 32 that are formed on thesupport plate body 31 to correspond to the plurality of holes 23 a ofthe bus bar 20 a. In this case, a size of a cross-section of the supporthole 32 may be greater than a size of a cross-section of the hole 23 aof the bus bar 20 a, and the bent portion 121 of the electrode tab 12may be brought into contact with one side of an outer circumferentialsurface of the support hole 32 and supported thereby. In this case, thebent portion 121 may be formed on the insulating portion 125 of theelectrode tab 12 as described above.

Accordingly, in a welding process that will be described below, the gapL₃ between the electrode tab 12 and the hole 23 a of the bus bar 20 amay be constantly maintained and a position of the electrode tab 12inserted into the hole 23 a may be fixed, and thus a welding line may beeasily traced when the electrode tab 12 is welded later. In addition,the bent portion 121 may be brought into close contact with one side ofan outer circumferential surface of a support hole 32 to prevent thelaser L from being directly applied to the battery cell 11.

Meanwhile, as an outer surface of the support plate may be coated withan insulating material or the support plate may be formed of aninsulating material and the plurality of electrode tabs may berespectively inserted into the plurality of support holes, an insulatedstate between the electrode tabs may be maintained.

Furthermore, the battery module 1 according to an embodiment of thepresent disclosure may further include the fixing plate 40, whichcouples and fixedly supports the bus bar 20 a and the support plate 30.

Specifically, the battery module 1 according to an embodiment of thepresent disclosure may further include the fixing plate 40 in which aplurality of bus bar exposure holes 42 are formed to correspond to theholes 23 a of the bus bar 20 a. In this case, the fixing plate 40 may belocated at an outer side of the bus bar 20 a, and may fixedly supportthe bus bar 20 a by being coupled to at least a portion of the supportplate 30 on at least a portion of the fixing plate 40. Further, thefixing plate 40 may be positioned to cover an outer surface of the busbar 20 a, and thus may protect the bus bar 20 a from foreign matter orthe like.

More particularly, the fixing plate 40 may include a plate-shaped fixingplate body 41 and the plurality of bus bar exposure holes 42 formed inthe fixing plate body 41 to correspond to the plurality of holes 23 a ofthe bus bar 20 a. In this case, a size of a cross-section of the bus barexposure hole 42 may be greater than the size of the cross-section ofthe hole 23 a of the bus bar 20 a. Preferably, the bus bar exposure hole42 may be formed to have a size such that the protruding portion 22 amay be exposed to the outside, and thus a welding portion may be easilytraced during welding.

Furthermore, the fixing plate 40 may be formed in a form in which aportion other than the bus bar exposure holes 42 surrounds an outersurface of the plate 21 a of the bus bar 20 a, and may be coupled to thesupport plate 30 with the bus bar 20 a interposed therebetween to stablyand fixedly support the bus bar 20 a.

Meanwhile, referring to FIGS. 11A and 11B, two or more secondarybatteries may be connected in parallel through the bus bars 20 a to begrouped into one parallel assembly 100, and a plurality of parallelassemblies 100 may be connected in series to form a battery module 1. Inthis case, two or more bus bars 20 a may be provided, and a terminalportion 25 a which can be connected to another external battery moduleor a charging and discharging device may be formed on at least a portionof each of the two bus bars 20 a located at both ends of one sidesurface of the battery module 1.

Specifically, each of the terminal portions 25 a may refer to a positive(+) pole or a negative (−) pole of the battery module 1 to which aplurality of parallel assemblies 100 are connected, and one of the twoterminal portions 25 a may be connected to the positive (+) pole and theother terminal portion may be connected to the negative (−) pole,according to an arrangement of electrodes of the plurality of parallelassembly 100.

Meanwhile, terminal support holes 44 may be formed at positionscorresponding to the terminal portions 25 a in at least a portion ofboth ends of the fixing plate 40, and the terminal portion 25 a may beinserted and fixed to the terminal support hole 44.

For example, as illustrated in FIG. 8 , two bus bars 20 a each havingthree holes may be provided, and terminal portions 25 a may be formed onat least a portion of each of the two bus bars 20 a located at both endsof one side surface of the battery module 1. Furthermore, as illustratedin FIG. 9 , a position of the bus bar 20 a may be fixedly supported bythe terminal portion 25 a being inserted into the terminal support hole44 formed on the fixing plate 40.

Furthermore, as the terminal portion 25 a protrudes to an outside of thefixing plate 40, the terminal portion 25 a may be exposed to the outsideof the fixing plate 40 even while the bus bar 20 a is surrounded by thefixing plate 40, and the terminal portion 25 a may be connected to anexternal battery module, a charging and discharging device, or the like.

Meanwhile, when the plurality of bus bars 20 a are provided as describedabove, at least one fixing member 43, which is located between theplurality of bus bars 20 a and fixedly supports a position of the busbar 20 a, may be formed on at least a portion of the fixing plate 40. Inthis case, at least one fixing member 43 may protrude from at least aportion of the fixing plate body 41 toward the bus bar 20 a. The numberof fixing members 43 formed may correspond to the number of the bus bars20 a. For example, when two bus bars 20 a are provided, as illustratedin FIG. 8 , one fixing member may be formed at one side of the fixingplate 40, and the fixing member 43 may be positioned between the two busbars 20 a to fixedly support the positions of the bus bars 20 a.

Furthermore, a fixing member insertion groove 33 corresponding to thefixing member 43 may be recessed in at least a portion of the supportplate 30 at the bus bar 20 a. Specifically, the fixing member 43protruding from the fixing plate 40 may be inserted into one side of thesupport plate 30, and the fixing member 43 may be positioned in thefixing member insertion groove 33 so that the fixing member 43 mayfirmly and fixedly support the bus bar 20 a.

Furthermore, the fixing plate 40 may include a plurality of fasteningprotrusions 411, which are formed by at least a portion of the fixingplate body 41 protruding toward the bus bar 20 a, and the fasteningprotrusions 411 may be coupled to at least a portion of the supportplate 30 so that the support plate 30 and the fixing plate 40 may becoupled to each other.

Specifically, a locking portion (not illustrated) may be formed at thefastening protrusion 411, a locking groove (not illustrated)corresponding to the locking portion may be formed on at least a portionof the support plate 30, and thus the fixing plate 40 and the supportplate 30 may be engaged and coupled to the bus bar 20 a interposedtherebetween through the fastening of the locking portion and thelocking groove. However, this configuration is merely an example, andthe present disclosure is not limited thereto. That is, it is sufficientfor the fastening protrusions 411 to be brought into contact with atleast a portion of the support plate 30 to be fastened and coupled.

As described above, the fixing plate 40 may be formed to surround all ofthe remaining portions other than the protruding portion 22 a of the busbar 20 a, and thus the possibility of electrical connection with othercomponents around the bus bar 20 a may be preemptively blocked when thebattery module 1 is used.

Meanwhile, at least one insertion protrusion 45 protruding toward thebus bar 20 a may be formed on a side surface of the fixing plate body 41at the bus bar 20 a. In this case, the bus bar 20 a may further includeat least one through-hole 26 a, which is formed at a positioncorresponding to a position of the insertion protrusion 45 at the plate21 a and through which the insertion protrusion 45 passes. Further, thesupport plate 30 may be formed on the support plate body 31 so that theinsertion protrusion 45 may be inserted therein, and the support plate30 may further include at least one fastening hole 34, which may becoupled to the insertion protrusion 45 when the insertion protrusion 45is inserted thereinto.

Specifically, the insertion protrusion 45, the through-hole 26 a, andthe fastening hole 34 may be formed at positions corresponding topositions of the fixing plate body 41, the plate 21 a, and the supportplate body 31, respectively. For example, the insertion protrusion 45may be formed at a position adjacent to the bus bar exposure hole 42.Accordingly, the through-hole 26 a may be formed at a position adjacentto the hole 23 a, and the fastening hole 34 may be formed at a positionadjacent to the support hole 32.

More particularly, when the fixing plate 40, the bus bar 20 a, and thesupport plate 30 are coupled as illustrated in FIG. 9 , the insertionprotrusion 45 may be inserted into the fastening hole 34 of the supportplate 30 through the through-hole 26 a of the bus bar 20 a. In thiscase, the insertion protrusion 45, which may be inserted into thefastening hole 34, and the fastening hole 34 may be coupled so that thesupport plate and the fixing plate 40 may be coupled, and the positionof the bus bar 20 a may be fixed.

Further, the insertion protrusion 45 may be thermally fused while theinsertion protrusion 45 is inserted into the fastening hole 34 throughthe through-hole 26 a so that the insertion protrusion 45 may beattached to one surface of the support plate body 31, and accordingly,the fixing plate 40, the bus bar 20 a, and the support plate 30 may becoupled so that the position of the bus bar 20 a may be stably andfixedly supported.

Meanwhile, the support plate 30 and the fixing plate 40 may be formed tohave a size corresponding to a cross-sectional area of a stackedstructure of the plurality of battery cells 11 in a stacking direction.Accordingly, an unnecessary volume of the battery module 1 may beminimized despite the volume of the support plate 30 and the fixingplate 40, and thus the bus bar 20 a and the electrode tabs 12 may befixedly supported while energy density of the battery module 1 is nothindered.

FIGS. 11A and 11B are front and rear views, respectively, of a batterymodule 1 according to an embodiment of the present disclosure. Asecondary battery at a left end of FIG. 11A is a secondary battery at aright end of FIG. 11B. The battery module 1 illustrated in FIGS. 11A and11B is in an electrically connected state.

Referring to FIGS. 11A and 11B, two or more secondary batteries 10 maybe connected in parallel through the bus bar 20 a to be grouped into oneparallel assembly 100, and a plurality of parallel assemblies 100 may beconnected in series to form a battery module 1.

For example, as described in FIG. 11A, when viewed from the front, threepositive (+) poles of the secondary batteries 10 may be connected inparallel through the bus bar 20 a to form the one parallel assembly 100a, and the parallel assembly 100 a may be arranged to be adjacent to aparallel assembly 100 b in which negative (−) poles are connected inparallel and connected to the parallel assembly 100 b in series.

Specifically, four parallel assemblies 100 a and 100 b having differentelectrodes may be provided on the basis of one direction of theplurality of secondary batteries 10 and may be connected in seriesthrough bus bars 20 a. That is, a total of twelve secondary batteries 10may be connected. However, this configuration is merely an example, andthe present disclosure is not limited thereto. That is, two secondarybatteries 10 having the same electrode may be connected in parallel toform one parallel assembly 100 and a plurality of parallel assemblies100 having different electrodes at one side thereof may be connected inseries to form one battery module 1.

As described above, in the battery module 1 according to an embodimentof the present disclosure, since the number of the secondary batteries10 constituting one parallel assembly 100 may be freely selected and thenumber of the parallel assemblies 100 to be connected in series may alsobe freely selected, a degree of freedom in configuring the batterymodule 1 may be improved, which may be achieved by the number of theholes 23 a formed in the bus bar 20 a being simply changed.

Further, the bus bar 20 a according to an embodiment of the presentdisclosure may further include a voltage sensing connection portion 200a formed on at least a portion of the plate 21 a. Specifically, thevoltage sensing connection portion 200 a may be connected to a voltagesensing module (not illustrated) for measuring a voltage of the parallelassembly 100 and the like. In this case, the voltage sensing module maybe a configuration, such as a voltage sensing circuit, a batterymanagement module, or the like located outside the battery module 1 andcapable of measuring and confirming a state of a voltage of the parallelassembly 100.

Meanwhile, in a welding process of the electrode tab 12 that will bedescribed below, a laser may be applied to an end surface of theelectrode tab 12 at predetermined intervals to the end surface of theelectrode tab 12 so that a plurality of electrode tab welding portions123 may be formed at the predetermined intervals. See FIG. 16A. However,the present disclosure is not limited thereto, and, as illustrated inFIG. 16B that will be described below, the laser may be continuouslyapplied to the end surface of the electrode tab 12 so that the electrodetab welding portion 123 may be formed to have a continuous shape in astraight line.

Further, although the terminal portion 25 a is not included in the busbar 20 a illustrated in FIGS. 11A and 11B, FIGS. 11A and 11B are viewsfor describing an electrical connection relationship between theplurality of secondary batteries 10 except that the terminal portion 25a is omitted, and the terminal portion 25 a may protrude from at least aportion of the bus bars 20 a at both ends of the plurality of bus bar 20a.

FIGS. 12A and 12B are cross-sectional views illustrating a bus bar 20 baccording to an embodiment of the present disclosure. FIG. 12A is across-sectional view illustrating the bus bar 20 b, and FIG. 12B is across-sectional view illustrating a state in which an electrode tab 12is inserted into a hole 23 b of the bus bar 20 b.

A protruding portion 22 b of a bus bar 20 b according to an embodimentof the present disclosure may include a tapered cross-section shape. Theprotruding portion 22 b may be formed to have a conical cross-sectionwith the hole 23 b positioned at the top of the conical cross-section.Hence, the sides of the protruding portion 22 b may be formed to beinclined surfaces. The protruding portion 22 b may be formed to have ashape such that a cross-section of an inner space of the protrudingportion 22 b is reduced near the hole 23 b. The protruding portion 22 bmay function to induce the electrode tab 12 to be inserted into the hole23 b due to an inclination thereof when the electrode tab 12 is insertedinto the hole 23 b.

FIGS. 13A and 13B are cross-sectional views illustrating a bus bar 20 caccording to an embodiment of the present disclosure.

Referring to FIGS. 13A and 13B, a bus bar 20 c according to anembodiment of the present disclosure may include a plate 21 c and aplurality of holes 23 c. The bus bar 20 c may include a plurality ofholes 23 c, which are formed in the plate 21 c at predeterminedintervals. A size, such as an area or the like, of the plate 21 c andthe positioning of the holes 23 c may correspond to the number and widthof the battery cells 11 and the positioning of the electrode tabs 12.Since a detailed description thereof is identical to that of the bus bar20 a according to an embodiment of the present disclosure above,overlapping descriptions will be omitted.

In this case, the plate 21 c may include protruding portions 22 c, whichare also referred to as tab connection portions 22 c. Each of the tabconnection portions 22 c may protrude from an outer periphery of each ofthe holes 23 c in a direction in which the electrode tab 12 protrudes,and the electrode tab 12 melted by the laser L may then be brought intocontact with the tab connection portion 22 c and electrically connectedto the bus bar 20 c when the battery cells 11 are electrically connectedby laser welding. The sides of each tab connection portion 22 c aresubstantially perpendicular to the plate 21 c. Hence, unlike theembodiment of FIGS. 12A and 12B wherein the sides of each protrudingportion is an inclined surface, in the embodiment of FIGS. 14A and 14B,the sides are substantially perpendicular to the plate 21 c.

Since the tab connection portion 22 c is formed on the plate 21 c,reflected light of the laser L may be minimized when the laser L isapplied for electrical connection between the battery cells 11.Accordingly, dispersion of energy of the laser L may be prevented andthe laser L having a specific amount of energy may be uniformly appliedduring welding. Thus a process error in the welding process may bereduced and a production speed of a battery module 1 may be improved.

FIG. 14A is a cross-sectional view illustrating the bus bar 20 caccording to an embodiment of the present disclosure, and FIG. 14B is across-sectional view illustrating a state in which the electrode tab 12is inserted into the hole 23 c of the bus bar 20 c.

Referring to FIG. 14B, the battery cell 11 may be arranged to beperpendicular to the ground, and the bus bar 20 c may be mounted on theelectrode tab 12 at an outer side of the battery cell 11. It should beapparent to those skilled in the art that the present disclosure isdescribed with reference to drawings in which the battery cells 11 maybe arranged in parallel to the ground, and thus a position of the busbar 20 c may be changed.

Referring to FIGS. 14A and 14B, the hole 23 c may be formed to have adepth L₆ relatively smaller to a length L₁ of the electrode tab 12, sothat the electrode tab 12, when it is inserted into one side of the busbar 20 c, may protrude from the other side of the bus bar 20 c. Forexample, the electrode tab 12 may preferably protrude by about 1 mm ormore from an outer end of the tab connection portion 22 c so that thelaser L is applied to the electrode tab 12 obliquely with respect to acentral axis of a direction d₁ of the length L₁ of the electrode tab 12.Further, the bus bar 20 c may be welded by applying only the electrodetab 12 without applying the bus bar 20 c in a welding process that willbe described below. On the other hand, when the electrode tab 12protrudes too much, the laser L should be repeatedly applied to theelectrode tab 12. Also, if the electrode tab 12 is not sufficientlymelted during the welding, the electrode tab 12 and the bus bar 20 c maynot be smoothly connected. Therefore, the electrode tab 12 preferablyprotrudes by about 3 mm or less.

Further, a bent portion 121 may be formed on the electrode tab 12. Inthis case, the bent portion 121 may be formed by a predetermined portionof the electrode tab 12 being bent. The bent portion 121 is not limitedto being formed by the predetermined portion of the electrode tab 12being bent, and a protruded portion may be formed at the predeterminedportion of the electrode tab 12.

In this case, since a detailed description of the bent portion 121 isidentical to that of the above-described electrode tab 12 according toan embodiment of the present disclosure, the overlapping descriptionswill be omitted.

Meanwhile, since a connection structure of the bent portion 121 of theelectrode tab 12 and the support plate 30, the fixing plate 40, and theparallel assembly 100 described in the specification is identical tothat of each of the battery modules 1 according to various embodimentsof the present disclosure above, overlapping descriptions thereof willbe omitted.

According to an embodiment, a battery module 1 may be manufactured bystacking a plurality of battery cells 11, arranging an electrode tab 12included in each of the plurality of battery cells 11 at one side of theplate 21 c of the bus bar 20 c adjacent a respective hole 23 c among aplurality of holes 23 c of the plate 21 c, inserting the electrode tabs12 in their corresponding holes 23 c, and electrically connecting theplurality of battery cells 11.

In an embodiment, the plurality of battery cells 11 may be electricallyconnected by laser welding the electrodes 12 to the plate after theelectrodes are positioned within their respective holes 23 c. A laser Lmay be applied only to the electrode tabs 12 as described above. Asdescribed above, when a bus bar 20 c is welded by applying the laseronly on the electrode tab 12, the electrode tabs 12 and the bus bar 20 amaybe coupled after the electrode tabs 12 melt sufficiently. Dislike aconventional method of melting and welding two base materials, problemof specific portions being connected while a portion is not welded asone of the two base materials is not melt sufficiently may be minimized.Thus a welding state may be visually checked, and quality and productionspeed of the battery module 1 may be significantly improved.

Furthermore, the welding may be performed on an end surface of theelectrode tab 12 at regular intervals, the laser L may be repeatedlyapplied to the end surface in a shape of a circle, and centers of thecircles may be located along an axis 122 of a direction d₂ of a lengthL₅ of the end surface of the electrode tab 12. As described above, thewelded portion of the electrode tab 12 may be uniformly melted bywobble-type welding performed by the circles being repeatedly formed tooverlap. Specifically, stability of a process of manufacturing thebattery module 1 may be improved in the welding process of the electrodetab 12 included in the battery cell 11 which is vulnerable to hightemperature.

Meanwhile, a support plate 30 may be arranged between the plurality ofbattery cells 11 and the bus bar 20 c, and the electrode tab 12 may bepositioned to pass through support holes 32 of the support plate 30.Specifically, the electrode tab 12 may be inserted at one side of theplate 21 c while passing through the support holes 32 of the supportplate 30, and thus may be arranged on at least a portion of theplurality of holes 23 c.

In this case, the electrode tab 12 may include the bent portion 121formed by being bent and folded, and the bent portion 121 may be broughtinto close contact with one side of an outer circumferential surface ofthe support hole 32 so that the electrode tab 12 may be fixedlysupported.

Further, as illustrated in FIG. 10 described above, a fixing plate 40may be arranged at the other side of the bus bar 20 a, and the positionof the bus bar 20 a may be fixedly supported by coupling the fixingplate 40 and the support plate 30.

Specifically, a plurality of insertion protrusions 45, which are formedby forming at least a portion of the fixing plate body 41 to protrude,may be formed on side surfaces of the support plate 30 of the fixingplate 40, and a plurality of fastening holes 34 corresponding to theinsertion protrusions 45 may be formed on at least a portion of asupport plate body 31. In this case, as described above, the insertionprotrusions 45 may be inserted in the fastening holes 34 and fused sothat the fixing plate 40 and the support plate 30 may be coupled withthe bus bar 20 a interposed therebetween, and a position of the bus bar20 a may be fixedly supported.

Meanwhile, a hole 23 a and a protruding portion 22 a that will bedescribed below may be exposed to the outside through a bus bar exposurehole 42 of the fixing plate 40, and thus an operator may easily trace awelding line when the electrode tab 12 and the bus bar 20 a are welded.

Since detailed descriptions of the support plate 30 and the fixing plate40 are identical to those of the battery module 1 according to anembodiment of the present disclosure described above, overlappingdescriptions will be omitted.

Meanwhile, in the plate 21 a of the bus bar 20 a, the protruding portion22 a may be formed at a position at which the hole 23 a is formed.Specifically, the protruding portion 22 a may be formed to create anentry space having a width L₄ into which the electrode tab 12 enters atone side of the protruding portion 22 a is reduced near the holes 23 a,and the insertion of the electrode tab 12 may be facilitated when theabove-described electrode tab 12 is inserted into the hole 23 a of theplate 201 a.

Furthermore, according to an embodiment of the present disclosure, theprotruding portion 22 b may be formed on the plate 21 b of the bus bar20 b at a position at which the hole 23 b is formed. Specifically, theprotruding portion 22 b may be formed to have a cross-section shapetapered toward the hole 23 b, and all of the holes 23 b may be formed tohave a tapered cross-section shape so that the insertion of theelectrode tab 12 into the hole 23 b may be facilitated during theinsertion of the electrode tab 12 into the hole 23 b.

FIG. 15 is a cross-sectional view illustrating a position at which laserwelding is performed on a protruding electrode tab 12 according to anembodiment of the present disclosure.

Referring to FIG. 15 , the battery module 1 may be manufactured bystacking a plurality of battery cells 11, inserting the electrode tab 12included in each of the plurality of battery cells 11 into one side ofthe plate 21 c in which the plurality of holes 23 c are formed andarranging the electrode tab 12 to protrude toward the other side of theplate 21 c in at least a portion of the plurality of holes 23 c, andelectrically connecting the plurality of battery cells 11.

Further, the battery module 1 may further include a bus bar assistancemember 24 formed of an insulating material such as plastic or the like.The bus bar assistance member 24 may be formed to surround all of theremaining portions other than the tab connection portion 22 c, and thusthe possibility of electrical connection with other components aroundthe bus bar 20 c may be preemptively blocked when the battery module 1is used.

Further, the electrode tab 12 may be inserted into one side of the plate21 c in which the plurality of holes 23 c are formed to protrude fromthe other side of the plate 21 c. In this case, the electrode tab 12 maybe arranged to protrude by a length of 1 to 3 mm from an outer end ofthe hole 23 c, as described above.

Meanwhile, the plurality of battery cells 11 may be electricallyconnected by laser welding, and the laser L may be applied only to theelectrode tab 12, as described above. As described above, when the busbar 20 c is welded by only the electrode tab 12 being applied withoutapplying the bus bar 20 c, problem of specific portions being connectedwhile a portion is not welded may be minimized in comparison to aconventional method of melting and welding two base materials. Thus awelding state may be visually checked, and quality and production speedof the battery module 1 may be significantly improved.

FIGS. 16A and 16B are views illustrating a state in which laser weldingis performed on an electrode tab 12 according to an embodiment of thepresent disclosure.

Referring to FIGS. 16A and 16B, welding may be performed on an endsurface of the electrode tab 12 at regular intervals. An enlarged viewin FIGS. 16A and 16B illustrates that welding is not performed in astraight line like a conventional laser welding, and the laser L isrepeatedly applied to the end surface of the electrode tab 12 in a shapeof a circle, and centers of the circles are located along an axis 122 ina direction d₂ of the length L₅ of the end surface. As described above,the welded portion of the electrode tab 12 may be uniformly meltedthrough wobble-type welding performed by the circles being repeatedlyformed to overlap. Specifically, welding may be effectively applied, andstability of a process of manufacturing the battery module 1 may beimproved in a welding process of the electrode tab 12 included in thebattery cell 11 which is vulnerable to high temperature.

Meanwhile, it is noted that the welding is not limited to beingperformed at regular intervals. As illustrated in FIG. 16B, the lasermay be continuously applied to the end surface of the electrode tab 12so that the electrode tab welding portion 123 may be formed to have acontinuous shape in a straight line.

FIGS. 17A and 17B are views illustrating a state in which a laser isapplied to the electrode tab 12 at an angle with respect to a directiond₁ of the length L₁ of the electrode tab 12 according to an embodimentof the present disclosure.

Referring to FIGS. 17A and 17B, the laser L may be applied obliquelywith respect to a central axis of a direction d₁ of the length L₁ of theelectrode tab 12 inserted into the hole and protruding therefrom.Accordingly, when the laser L is applied obliquely to the end surface ofthe electrode tab 12, it is possible to reduce errors and accidents byminimizing the possibility of the laser L being directly applied to thebattery cell 11. As the laser L is obliquely applied, the weldingprocess on the end surface of the electrode tab 12 may be visuallyconfirmed, and thus quality and production speed of the battery module 1may be improved. However, if necessary, the laser L may be appliedperpendicularly to the end surface of the electrode tab 12.

Meanwhile, in this case, the laser L may be applied to the end surfaceof the electrode tab 12, as illustrated in FIG. 17A, but the presentdisclosure is not limited thereto, and the laser L may be applied to oneside surface of the electrode tab 12 according to a material of theelectrode tab 12, as illustrated in FIG. 17B. Furthermore, it should beapparent to those skilled in the art that the laser L may be appliedaround the bus bar 20 c.

According to the present disclosure, a battery module is provided whichallows the number of assembling processes to be reduced for electricallyconnecting a plurality of battery cells.

Further, a battery module capable of preventing deformation of shapes ofelectrode tabs due to a shape of a bus bar being deformed can beprovided.

Further, a battery module of the present disclosure allows costs to bereduced since the number of processes may be reduced.

Further, when a plurality of battery cells are electrically connected,electrode tabs can be uniformly melted.

Further, when a plurality of battery cells are electrically connected bywelding or the like, a connection state can be visually confirmed.

While representative embodiments of the preset disclosure have beendescribed above in detail, those skilled in the art should understandthat the embodiments may be variously modified without departing fromthe scope of the present disclosure as defined in the appended claims.

What is claimed is:
 1. A method for manufacturing a battery module,comprising: forming an electrode tab extended from a battery cell, theelectrode tab having a bent portion and a straight portion; insertingthe electrode tab into a hole of a bus bar; and securing the electrodetab to the bus bar.
 2. The method of claim 1, wherein forming theelectrode tab includes bending a portion of the electrode tab.
 3. Themethod of claim 2, wherein the portion of the electrode tab forms thebent portion.
 4. The method of claim 3, wherein the bent portion iselectrically insulated.
 5. The method of claim 3, wherein the bentportion forms a front surface and a rear surface, wherein one of thefront surface and the rear surface is concave, and wherein another ofthe front surface and the rear surface is convex.
 6. The method of claim1, wherein forming the electrode tab includes forming a chamfer portionat a portion of an edge of the electrode tab.
 7. The method of claim 1,further comprising assembling a bus bar assembly, wherein the bus barassembly includes the bus bar, a support plate, and a fixing plate. 8.The method of claim 7, wherein assembling the bus bar assembly includes:placing the bus bar between the support plate and the fixing plate; andfixing the fixing plate to the support plate.
 9. The method of claim 8,wherein the electrode tab is inserted into the support plate, the busbar, and the fixing plate, sequentially.
 10. The method of claim 1,wherein securing the electrode tab to the bus bar includes welding theelectrode tab to the bus bar.
 11. The method of claim 10, wherein thestraight portion extends from the bent portion, wherein the straightportion is inserted into the hole of the bus bar, and wherein thestraight portion is welded to the bus bar.
 12. The method of claim 10,wherein the electrode tab is welded to the bus bar by wobble type. 13.The method of claim 1, further comprising forming the bus bar, whereinthe bus bar includes a plate and the hole formed on the plate.
 14. Themethod of claim 13, wherein forming the bus bar includes forming thehole on the plate.
 15. The method of claim 14, wherein the hole isnarrower outward from an inner surface of the plate, wherein the innersurface of the plate faces the battery cell.
 16. The method of claim 13,wherein the bus bar includes a protrusion formed on the plate, whereinthe protrusion is positioned at the hole of the bus bar.